Actress Shailene Woodley is cutting her long hair for her role in “The Fault in Our Stars” and donating it, and she wants others to follow her example.

Woodley is portraying Hazel, a teen diagnosed with cancer, who is the main character in the film adaptation of John Green’s bestselling young adult novel. Woodley will be cutting her hair this weekend and giving it to the group Children With Hair Loss, which helps children who lost their locks to cancer or other sicknesses by making wigs.

“I couldn’t be more amped,” she wrote. “Not only do I have the opportunity to externally shift my current establishment of self, but I have the blessed gift of donating my long locks to a wonderful organization who will then create a wig for someone in need. WHAT AN HONOR.”

“When Shailene told me about this, I immediately thought there might be people in nerdfighteria who want to join her,” Green wrote on his Tumblr. (Green fans refer to themselves as Nerdfighters.) “(We already have one convert joining in: Shailene’s mom!) So if you have eight or more inches of spare hair, consider donating it to Children With Hair Loss. And if you do, let me know via the tags hairforhazel or itgrowsback, so I can put together some pictures/reblog your beautiful faces. I want to be clear that this was entirely Shai’s idea. (I don’t even think the studio knows about it.) I hope if you’re able, you’ll consider joining Shai in donating.”

Woodley added a P.S. to her Tumblr post, writing that Green had been writing to her and giving her information on how many people were responding.

“I am in tears,” she wrote. “HOW GRATEFUL I AM FOR OUR ABILITY TO GIVE!”

Many people have already posted on Twitter using the hashtags #hairforhazel or #itgrowsback, supporting the cause or describing how they’ve cut their own hair.